- Please check and comment entries here.
Aspartyl-tRNA Synthetase 2, Mitochondrial: The DARS2 gene provides instructions for making an enzyme called mitochondrial aspartyl-tRNA synthetase.
1. Normal Function
This enzyme is important in the production (synthesis) of proteins in cellular structures called mitochondria, the energy-producing centers in cells. While most protein synthesis occurs in the fluid surrounding the nucleus (cytoplasm), some proteins are synthesized in the mitochondria.
During protein synthesis, in either the mitochondria or the cytoplasm, a type of RNA called transfer RNA (tRNA) helps assemble protein building blocks (amino acids) into a chain that forms the protein. Each tRNA carries a specific amino acid to the growing chain. Enzymes called aminoacyl-tRNA synthetases, including mitochondrial aspartyl-tRNA synthetase, attach a particular amino acid to a specific tRNA. Mitochondrial aspartyl-tRNA synthetase attaches the amino acid aspartic acid to the correct tRNA, which helps ensure that aspartic acid is added at the proper place in the mitochondrial protein.
2. Health Conditions Related to Genetic Changes
2.1 Leukoencephalopathy with Brainstem and Spinal Cord Involvement and Lactate Elevation
At least 25 mutations in the DARS2 gene have been identified in people with leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL), a condition that affects the brain and spinal cord and causes difficulty walking. The most common mutation that causes this condition disrupts the way genetic information is pieced together to make a blueprint for producing the mitochondrial aspartyl-tRNA synthetase enzyme. Most copies of the blueprint are pieced together incorrectly, which prevents the enzyme from being produced. However, some copies are pieced together correctly, and a small amount of normal enzyme is made. Other mutations change single amino acids in the enzyme. This type of mutation results in decreased mitochondrial aspartyl-tRNA synthetase enzyme activity. With reduced activity, the enzyme has difficulty adding aspartic acid to the tRNA, which hinders the addition of this amino acid to mitochondrial proteins.
It is unclear how the gene mutations lead to the signs and symptoms of LBSL. Researchers do not understand why reduced activity of mitochondrial aspartyl-tRNA synthetase specifically affects certain parts of the brain and spinal cord.
3. Other Names for This Gene
aspartate tRNA ligase 2, mitochondrial
aspartyl-tRNA synthetase, mitochondrial
aspartyl-tRNA synthetase, mitochondrial precursor
This entry is adapted from https://medlineplus.gov/genetics/gene/dars2
- Lin J, Chiconelli Faria E, Da Rocha AJ, Rodrigues Masruha M, Pereira Vilanova LC, Scheper GC, Van der Knaap MS. Leukoencephalopathy with brainstem and spinalcord involvement and normal lactate: a new mutation in the DARS2 gene. J ChildNeurol. 2010 Nov;25(11):1425-8. doi: 10.1177/0883073810370897.
- Scheper GC, van der Klok T, van Andel RJ, van Berkel CG, Sissler M, Smet J,Muravina TI, Serkov SV, Uziel G, Bugiani M, Schiffmann R, Krägeloh-Mann I,Smeitink JA, Florentz C, Van Coster R, Pronk JC, van der Knaap MS. Mitochondrial aspartyl-tRNA synthetase deficiency causes leukoencephalopathy with brain stemand spinal cord involvement and lactate elevation. Nat Genet. 2007Apr;39(4):534-9.
- Uluc K, Baskan O, Yildirim KA, Ozsahin S, Koseoglu M, Isak B, Scheper GC,Gunal DI, van der Knaap MS. Leukoencephalopathy with brain stem and spinal cordinvolvement and high lactate: a genetically proven case with distinct MRIfindings. J Neurol Sci. 2008 Oct 15;273(1-2):118-22. doi:10.1016/j.jns.2008.06.002.
- van der Knaap MS, van der Voorn P, Barkhof F, Van Coster R, Krägeloh-Mann I,Feigenbaum A, Blaser S, Vles JS, Rieckmann P, Pouwels PJ. A newleukoencephalopathy with brainstem and spinal cord involvement and high lactate. Ann Neurol. 2003 Feb;53(2):252-8.